1. Field of the Invention
The present invention relates to a current-spare switching control system, more particularly, it relates to a current-spare switching control system provided for a data processing system having a current data processor, a spare data processor, a fault supervisor for supervising the fault of these processors, and switching units for switching from the current data processor to the spare data processor or vice versa.
2. Description of the Related Art
In general, a data processing system has a current data processor and a spare data processor to ensure the reliability of data processing. The current data processor usually runs in a normal state, but it is immediately switched to the spare data processor when the fault occurs in the current data processor. In this case, the fault is detected by a fault supervisor which generates a switching signal to switch the switching units.
The fault supervisor usually has an internal microprocessor for supervising the fault of these processors and generating the switching signal to switch the switching units. The switching units, however, accidentally operate in error due to an error signal caused by reckless operation of the internal microprocessor of the fault supervisor. Accordingly, it is necessary to ensure correct operation of the switching units.